1. Field of the Invention
The present invention relates to the field of flat panel displaying, and in particular to a liquid crystal display panel repairing method and repairing system.
2. The Related Arts
A thin-film transistor (TFT) is a key structure of an active matrix liquid crystal display (TFT-LCD) and thus, whether the TFT matrix is good or not is vital to the quality of the TFT-LCD. However, the array process that is used to form the TFT structure is complicated and sophisticated. During the cyclic operations of the process, defects of the TFT are often generated, such as defects of electrode shorting or electrode breaking for channels, source terminals, drain terminals, and gate terminals or defects of shorting or breaking associated with wiring for scan lines and signal lines, and defects of storage capacitor electrodes and pixel electrodes. Thus, to cope with these defects, a typical array process involves a laser CVD (Chemical Vapor Deposition) repairing step after the process of forming gate terminals and source/drain terminals. With the progress of the TFT-LCD in a direction toward high resolution and high fineness, to ensure a TFT is manufactured to be completely defect free is generally not realistic. Thus, repair of TFT, particularly fine repair of TFT, becomes very important.
Laser CVD is a technique that uses laser chemical reaction to directly deposit a micro-film, in which laser is used to heat or to directly act on gas molecules to break the gas molecules for being then deposited on a substrate to form a film. Laser CVD has the following advantages: (1) micro area deposition, high spatial resolution, and being controllable, area not irradiated by laser being not subjected to thermal influence; (2) being capable of realizing efficient temperature rise in a specific area to reach the decomposition temperature of the chemical substance attached to the undersurface of the substrate and fast deposition; (3) being free of pollution and contamination and operation being easy; and (4) being capable of use in combination with other laser processing techniques. Based on such advantages, laser CVD demonstrates a value of important application to repairing line breaking or surface breaking of a TFT array. Heretofore, the laser CVD repairing method that is used in TFT wiring generally uses chromium hexacarbonyl (Cr(CO)6) or tungsten hexacarbonyl (W(CO)6) as a reactant gas to allow for deposition of a metal line of chromium (Cr) or tungsten (W) to re-joint the circuit. However, such a repaired portion has inconsistent conductivity, which will leads to thermal stress when subjected to application of heat load and consequently leading to a potential problem of reliability of the repaired spot. Further, the substance used, Cr(CO)6 and W(CO)6, is a substance that is extremely toxicant and is harmful to the environment.
Graphene is a new type of nano-carbon material demonstrating supper conductivity of electricity and heat and mechanical property. Thus, if graphene is used to replace Cr or W for deposition on a breaking defect, then due to the excellent capability of graphene for transmission of electrical charges and thermal energy and excellent extensibility, the reliability of the repaired spot can be enhanced. Heretofore, the methods that are used to grow graphene include mechanical exfoliation, silicon carbide (SiC) epitaxial growth, oxidation and reduction, and chemical vapor deposition, among which CVD is the most commonly used method with which graphene can grow with less defects and better quality. On the other hand, growing graphene with CVD process uses a material that is readily commonly available hydrocarbons, which is more secure and safer that the material used to deposit W or Cr and also has a lower cost. The process for manufacturing graphene with CVD is to have a carbon-contained gas, such as hydrocarbons, cracked under a high temperature into carbon atoms deposited on an undersurface of a substrate to form graphene. The heating method that is commonly adopted to generate the high temperature is heating with a resistance wire. However, this manner has a low rate of rising or lowering temperature and may set the entire substrate in the high temperature, making it not possible to realize selective deposition in micro areas. Using this method to repair the defects of a TFT-LCD may cause damages to various structures.